We just noticed, that senders got several "550 5.1.0 Address rejected" bounces even though postfix logs no permanent errors.
Oct 11 17:19:13 kop01 postfix/lmtp[5711]: E759E301412: to=<adm...@domain.tld>, relay=127.0.0.1[127.0.0.1]:2003, delay=13, delays=0/0.01/13/0, dsn=4.0.0, status=undeliverable (host 127.0.0.1[127.0.0.1] refused to talk to me: 421 internal error: OpenResolveAddrFolder failed) Isn't status=undeliverable a 5xx reject? Am Do., 11. Okt. 2018 um 19:14 Uhr schrieb Wietse Venema < wie...@porcupine.org>: > Stefan Bauer: > > Dear Users, > > > > we have the following in place: > > > > smtpd_recipient_restrictions = reject_unknown_recipient_domain, > > reject_unverified_recipient > > unverified_recipient_reject_code = 550 > > unknown_address_reject_code = 550 > > > > today, we had an issue with our groupware so the following was happening: > > > > NOQUEUE: reject: RCPT from unknown[ip]: 450 4.1.1 <adm...@domain.tld>: > > Recipient address rejected: unverified address: Address verification in > > progress; from=<m...@intmon01.int.domain.tld> to=<adm...@domain.tld> > > proto=ESMTP helo=<intmai01.int.domain.tld> > > Oct 11 17:19:13 kop01 postfix/lmtp[5711]: E759E301412: > to=<adm...@domain.tld>, > > relay=127.0.0.1[127.0.0.1]:2003, delay=13, delays=0/0.01/13/0, dsn=4.0.0, > > status=undeliverable (host 127.0.0.1[127.0.0.1] refused to talk to me: > 421 > > internal error: OpenResolveAddrFolder failed) > > NOQUEUE: reject: RCPT from jir01.int.domain.tld[ip2]: 450 4.1.1 > > <demo.u...@domain.tld>: Recipient address rejected: unverified address: > > host 127.0.0.1[127.0.0.1] refused to talk to me: 421 internal error: > > GetSession failed; from=<j...@domain.tld> to=<demo.u...@domain.tld> > > proto=ESMTP helo=<jir01.int.domain.tld> > > > > How do we reject unknown destinations / recipients still with a perm. > > error, but be more robust against temp errors like the ones above? > > As a matter of principle, I would consider it a bug if Postfix did > a 5XX reject after Postfix received a 4XX error. It's basic error > propagation hygiene. > > Wietse > > Wietse >
